If you’ve never been on a bicycle cruiser ride before, here’s what happens. You and your party gather someplace in town and maybe have some beers and/or dinner. Then you ride. The city and the night are yours. If you’re lucky, one of you is on a Soul Cycle, supplying the soundtrack.

The audio is thrillingly crisp, far better than any car stereo, thanks to no engine and less tire noise. You pedal, steer, and move to the beat, and some of your friends sing along, but others chat and laugh, steering in and out of different conversations. As the sky darkens, Down Low Glow tubes spill rolling pools of vivid, colored light onto the pavement below. Every pedestrian that your group passes smiles, waves, sways to the beat, or shouts “Right on!” and throws you a thumbs up. (But interestingly, people who are shut inside of cars tend not to acknowledge you.)

“Bikes are better social tools than cars,” notes Paul “Fossil Fool” Freedman, the San Francisco-based inventor, alpha rider, and merchant of the Soul Cycle in its many incarnations. “You can stop anywhere, talk, interact. If you ask a driver whether they want more cars on the road, they’ll say no, but ask a cyclist if they want more bikes, and they’ll say yes.”

Freedman’s Soul Cycles are ultimate party bikes, low-slung cruisers with slick lighting and detailing, seating for two, and gut-thumping sound systems. Freedman’s original inspiration came from a manager at the bike shop where he worked during high school, Buddy Bob, who lit up local night biking events with a recumbent that towed a stereo and a beer keg.

A few years later, after he graduated from Harvard, Freedman moved to San Francisco and started working for Xtracycle, a company that makes “sport utility bicycle” frame extensions.

Using car stereo components, the Xtracycle gang put together their Salsa Cycle for a promotional tour of Utah and Colorado, and on a warm summer’s night riding along to James Brown’s “Same Beat,” Freedman was hooked.

Before the Soul Cycle, bike audio meant either tinny little systems that clip onto handlebars, or clunky assemblages clamped to racks. Freedman started refining the form, putting controls in front to make them reachable while riding. The latest ones transmit the music signal wirelessly from bike to bike, to enable mob surround sound. Soul Cycle backrests, which house the amp, mixer, and battery, have evolved from wood boxes to rounded bamboo shapes to sculpted fiberglass with colored lights.

Freedman’s new Chopper model dispenses with the Xtracycle base completely, substituting a custom frame he co-designed with Curtis Inglis. The Chopper also has a curved, laminated, carbon-fiber and bamboo seat post that you can swing and lock into different positions while riding, to switch between hill-climbing, commuting, and low-rider cruising mode.

Freedman’s custom Soul Cycles are priced for high rollers, but for the rest of us he sells products that let you turn your own ordinary bike into a cruise-compliant party machine. The Down Low Glow is a ground-effects kit that splashes colored light down onto the pavement, a rare instance where something unimpeachably cool also enhances safety.

The Soul Cycle Head Unit, based on the hacker fav-orite T-Amp amplifier and a Rolls Mini Mixer, hooks up to your own speakers to play music and other inputs. As Freedman explains, “I start with fantasy projects, and learn from those how to scale back for products.”

Through Xtracycle’s nonprofit spinoff Worldbike, Freedman met Nate “The Juice Pedaler” Byerley, another biketrepreneur with complementary experience in sustainable party technology. After moving to Berkeley in 2001, Byerley envisioned selling some sort of food off the back of a bike. He determined that tacos were unworkable, then read about a bike-powered blender in Humboldt. Intrigued, he built one himself, running the blender off of a friction wheel on the rear tire, and securing the pitcher with a wooden collar on the back platform of an Xtracycle. Holding the pitcher tight proved difficult, but Byerley discovered the perfect part to replace the wood collar: an offset closet flange, a common toilet tank component made from ABS plastic.

With the new part, the Byerley Bicycle Blender was ready to take on the road. During the summer of 2005, Byerley showed it off at ecology and music festivals throughout the West Coast and demoed it on MTV, selling numerous blenders and many more $5 human-powered smoothies. Byerley has been selling his bicycle blenders ever since.

Byerley’s ingenuity isn’t limited to pedal power. Soon after his wife, Kaety, gave birth to their daughter, Davis, this past January, Byerley built a baby bike seat. Kaety was skeptical until she saw what he had created: a secure platform over the front wheel with a rear-facing infant car seat that keeps Davis in constant eye contact with Byerley. The three of them now ride (carefully) together, even on nighttime cruiser rides. “Like with dolphins,” Byerley explains, “the baby rides in the middle of the pack.”

Freedman and Byerley joined forces in 2004 as Rock the Bike, a company dedicated to their various products and projects. They moved into a space in Tinker’s Workshop in Berkeley, a facility that already housed Worldbike and the Bicycle-Friendly Berkeley Coalition (BFBC). Following the example of the workspace’s community-oriented owner

Nick Bertoni — a Vietnam vet, peace activist, and ex-Exploratorium exhibit builder — Rock the Bike hires local high school kids, teaches them how to use tools, and pays them to build Down Low Glow kits, Soul Cycle Head Units, the B3 Mini (Byerley’s latest bike blender), and other homegrown products in runs of 50–100. To help the bottom line, Rock the Bike also sells other people’s products that they like, including Incredibell bells and Brooks leather saddles.

Last year, local musician Gabe Dominguez visited Rock the Bike to see if they could build a human-powered PA system for an all-bike concert tour he was planning with his band, Shake Your Peace.

Freedman and Byerley combined their expertise to produce exactly what Dominguez wanted: a 200-watt system on the back of a bike with a heavy-duty stand for stationary mode and enough capacitor power to smooth over pedaling pauses of up to 15 seconds.

Shake Your Peace relied on the system during their 700-mile bike tour of Utah in May, and invited audience members to pedal-power each song. Audiences jumped at the chance to help, and the only mishap came when a large male volunteer wearing a pink unitard pedaled too vigorously and fried a capacitor.

Freedman and Byerley have more human-power ideas to pursue: a bigger concert PA system powered by multiple pedalers. A bike with integrated, plug-in power-generation capacity. A line of premium bicycles where all the power used to cut, weld, and finish the frame comes from pedaling. As Byerley explains, “There’s something about human power that people are drawn to, but it’s hard to fit into the current economic system. We’re trying to stretch that in every direction and find out where the niches exist.” (Meanwhile, Byerley’s friend Mike Taggett is working on energy-producing exercise equipment.)

Through all their inspiration and perspiration, Rock the Bike leads regular cruiser rides around the Bay Area, and their website (rockthebike.com) lists and promotes rides in other locations. Nighttime cruiser rides are payback time for all the hard work — and not just because they show off the merch. As Freedman explains, “It takes a long time to build one of these bikes, but then you’re out on a ride and you get some kids dancing on a pier or freestyling to the music, and it’s totally worth it.”